Site-specific interaction of vaccinia virus topoisomerase I with base and sugar moieties in duplex DNA Journal Article


Authors: Shuman, S.; Turner, J.
Article Title: Site-specific interaction of vaccinia virus topoisomerase I with base and sugar moieties in duplex DNA
Abstract: Vaccinia DNA topoisomerase specifically binds and forms a covalent adduct at DNA sites containing a conserved sequence element 5′(C/T)CCTT↓ in the scissile strand. The molecular interactions that contribute to recognition of the CCCTT motif in a synthetic DNA substrate have been examined using modification interference, modification protection, and analog substitution techniques. We report that topoisomerase makes contact with guanine nucleotide bases of the pentamer motif complementary strand (3′GGGAA) within the major groove of the DNA helix and that alteration of the binding surface by chemical modification is deleterious to the interaction. Additional contacts are made with guanine residues located outside the pentamer element. The enzyme is unable to form a covalent adduct with synthetic RNA substrates. Analysis of the cleavage of DNA duplexes containing 2′OMe sugars suggests that the inability of the vaccinia topoisomerase to cleave either an RNA duplex or an RNA:DNA hybrid can be accounted for by the interfering effects of a 2′ sugar substituent at two or more sites within the pentamer. Interaction with the sugar at the +2T nucleotide appears to be the most critical, as judged by the effects of single sugar substitutions.
Keywords: methylation; enzyme substrate; rna; dna; double stranded dna; dna modification; molecular sequence data; guanine; molecular recognition; substrate specificity; vaccinia virus; base sequence; binding site; dna adduct; dna sequence; binding sites; nucleic acid hybridization; nucleic acid conformation; enzyme specificity; carbohydrates; dna topoisomerase; dna topoisomerases, type i; protein dna interaction; vaccinia; dna rna hybridization; nucleotides; dna strand; uracil; virus enzyme; inosine; priority journal; article; dna base; support, non-u.s. gov't; support, u.s. gov't, p.h.s.
Journal Title: Journal of Biological Chemistry
Volume: 268
Issue: 25
ISSN: 0021-9258
Publisher: American Society for Biochemistry and Molecular Biology  
Date Published: 1993-09-05
Start Page: 18943
End Page: 18950
Language: English
PUBMED: 7689562
PROVIDER: scopus
DOI/URL:
Notes: Article -- Export Date: 1 March 2019 -- Source: Scopus
Citation Impact
MSK Authors
  1. Stewart H Shuman
    514 Shuman